JP2009033315A - Communication system by qam system, communication method therefor, and receiving apparatus and method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a communication system by a QAM (quadrature amplitude modulation) system and its communication method, and a receiving apparatus and its method. <P>SOLUTION: In this digital communication system, a transmission apparatus 10 generates a transmission signal 116 with a CRC (cyclic redundancy check) bit added thereto, and the receiver 30 performs demapping of a symbol string 134, based on a signal 132 by 64QAM system in a demapping circuit 34, to obtain a bit string 136 regardless of which system the received signal 132 is transmitted by either 16QAM system and 64QAM system, and can determine a data rate, without the need for a demapping circuit for 16QAM system or notification of data rate change, when a thinning circuit 38 performs thinning processing of the bit string 136 in accordance with a CRC detection result 138 based on the bit string 136 by a CRC detection circuit 36. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a communication system that communicates data using a quadrature amplitude modulation (QAM) method, a communication method thereof, a receiving apparatus, and a reception method thereof.

  Conventionally, in a digital communication system, the data rate of transmitted / received data and the communication quality have a trade-off relationship. In most wireless communications and some wired communications, communication quality changes over time. For example, communication systems such as ADSL and wireless LAN improve the total communication speed by dynamically changing the data rate. It is generally done.

  As a method for changing the data rate in this way, a method such as changing the symbol rate, changing the number of bits per symbol, or changing the coding rate of the error correction code can be considered.

  For example, some transmission apparatuses in conventional digital communication systems change the number of bits per symbol by changing the modulation method to 16QAM or 64QAM in accordance with an instruction from a control unit. 16QAM is a method of assigning 4 bits to one symbol, and 64QAM is a method of assigning 6 bits to one symbol. Similarly, a receiving apparatus in such a system changes the demodulation method from 16QAM to 64QAM in response to an instruction from the control unit.

  In such a transmission apparatus, mapping processing in the 16QAM system is performed, 16 points are evenly arranged in a space where the I channel and the Q channel are orthogonal, and 4-bit data is allocated to each point. This equality means a state in which the mutual distances between the points are equal. Arbitrary data may be assigned by assigning 16-QAM 4-bit data so that transmission and reception correspond to each other at a predetermined point in the IQ space, but a difference from bits assigned at adjacent points, that is, Hamming It is desirable to set the distance to 1. As described above, the state in which the Hamming distance is 1 is established at all points, so that the transmission signal according to the 16QAM system can be converted into a Gray code.

  Further, the transmission method described in Patent Document 1 can share the signal arrangement regardless of the modulation method by using the number of bits corresponding to the modulation method from the lower bits. For example, 16QAM and 64QAM share a common non- Perform signal arrangement for encoding.

In this method, the received signal is divided into uncoded bits and coded bits, the uncoded bits are hard-decided for each sub-bit, and the coded bits are decoded and then re-encoded to determine the uncoded bits. When the result is input to the non-encoded bit selector, a representative symbol corresponding to the re-encoded encoded bit is selected and output as decoded data. At this time, in the case of 16QAM, only the lower 2 bits of the uncoded bits are used, and in the case of 64QAM, only the lower 4 bits of the uncoded bits are used.
JP 08-265160

  However, in the conventional digital communication system, the data rate cannot be accurately changed unless the modulation schemes are switched at the same timing in mapping in the transmitting apparatus and demapping in the receiving apparatus.

  In addition, each of the transmission device and the reception device must have a plurality of types of mapping circuits and demapping circuits, which increases the circuit scale.

  In order to match the data rate switching timing between the transmission side and the reception side, for example, by wireless LAN, data is divided into units called packets, and a bit string including control information called a header is attached to each packet at the head. it can.

  However, in this case, the header must be modulated with 16QAM, and the modulation method of the subsequent data portion is specified. However, since only the header portion cannot be sent, the data rate is lowered. Further, an extra operation such as analysis of the contents of the header and switching of the data rate according to the analysis result is added.

  It is an object of the present invention to provide a communication system and a communication method thereof, a receiving apparatus, and a reception method thereof that can eliminate such drawbacks of the prior art and can efficiently switch the QAM modulation method.

  In order to solve the above-described problems, the present invention provides a digital communication system that transmits and receives packet data at a data rate corresponding to any one of a plurality of QAM schemes. Redundancy Check (CRC) bit is added, the modulation method of the data to be transmitted is selected from these multiple QAM methods, and the selected QAM among the multiple mapping processes corresponding to each of these multiple QAM methods A mapping process corresponding to the system is performed on the data to be transmitted, a transmission unit that modulates and transmits the data after the mapping process, a received data is demodulated, and a predetermined demapping process is performed. CRC detection is performed based on the data after mapping processing, and if CRC cannot be detected, the data after this predetermined demapping processing is thinned out Characterized in that it comprises a receiving means for performing.

  In addition, a communication method for packet data transmitted / received at a data rate corresponding to any of the QAM methods among a plurality of QAM methods, when transmitting this packet data, adds a CRC bit to the data to be transmitted, The modulation method of the data to be transmitted is selected from these multiple QAM methods, and the mapping process corresponding to the selected QAM method among the multiple mapping processes corresponding to each of these multiple QAM methods should be transmitted The data after the mapping process is modulated and transmitted, and when the packet data is received, the received data is demodulated and subjected to a predetermined demapping process. CRC detection is performed based on this, and if the CRC cannot be detected, the data after this predetermined demapping process is thinned out. .

  Furthermore, the receiving device that receives packet data that is mapped according to any of the QAM schemes and transmitted at a data rate according to the QAM scheme is configured to receive the packet data with the CRC bit added. The received data is demodulated and subjected to a predetermined demapping process. CRC detection is performed based on the data after the predetermined demapping process, and if the CRC cannot be detected, the predetermined demapping process is performed. A thinning process is performed on the data.

  Also, the method of receiving packet data that has been mapped according to one of the multiple QAM methods and transmitted at the data rate according to the QAM method receives this packet data with the CRC bit added. The received data is demodulated, subjected to a predetermined demapping process, CRC detection is performed based on the data after the predetermined demapping process, and if the CRC cannot be detected, the data after the predetermined demapping process It is characterized in that a thinning-out process is performed on.

  According to the digital communication system of the present invention, the mapping circuit of the transmission device arranges the 16QAM system symbols so that they overlap the 64QAM system symbols in space, and among the 64QAM symbols, the upper 4 of the 16 symbols that overlap. A bit sequence is allocated so that the bits and 4 bits of the 16QAM symbol are the same, and transmission data is generated so as to be a Gray code in both the 64QAM system and the 16QAM system. Therefore, a receiving apparatus that receives such transmission data Then, when 64QAM demapping is performed on received data, if the lower 2 bits of the demapped data are discarded, 16QAM demapping is performed, and therefore, it is not necessary to provide a 16QAM demapping circuit in the receiving apparatus.

  Also, in the digital communication system of the present invention, the transmission device adds CRC bits to generate transmission data. When a signal modulated by the 16QAM system is received, if the received signal is demodulated by the 64QAM system, CRC detection is performed. The data rate at the time of transmission of the received signal can be automatically determined according to the result. Therefore, the header for notifying the change of the data rate from the transmission side to the reception side is not required, the data rate is improved, and the analysis of the contents of the header is not required, so that the system can be simplified.

  Next, embodiments of a transmission apparatus and a reception apparatus in a digital communication system according to the present invention will be described in detail with reference to the accompanying drawings. For example, the transmission device 10 transmits a transmission signal based on a desired packet in variable rate communication using a quadrature amplitude modulation (QAM) system. As shown in FIG. Cyclic Redundancy Check (CRC) generation circuit 12 adds a CRC bit to the input packet, and control unit 14 controls switch unit 16 to input the input packet to 16QAM mapping circuit 18 or 64QAM mapping circuit 20, and the mapped packet Is converted into a transmission signal by the modulator 24 via the switch unit 22 and transmitted.

  The receiving device 30 receives and processes a signal transmitted from another device in variable rate communication using the QAM method, and converts the received signal into a symbol string by the demodulator 32 as shown in FIG. The 64QAM demapping circuit 34 converts the bit string into a bit string, the CRC detection circuit 36 detects a CRC bit from the bit string, and the thinning circuit 38 performs a thinning process on the bit string in accordance with the detection result. Note that portions not directly related to understanding the present invention are not shown and redundant description is avoided.

  The digital communication system of the present invention selects one of a plurality of modulation schemes and transmits / receives packet data at a data rate corresponding to the scheme.

  The CRC generation circuit 12 inputs a packet 102 that is data to be transmitted, that is, a bit string, and generates a CRC bit according to, for example, a predetermined generation polynomial, and adds the CRC bit to the packet 102. A new packet 104 is generated and supplied to the switch unit 14.

  The control unit 14 selects the modulation method of the signal transmitted by the device 10, and supplies the control signal 106 indicating the selection result to the switch unit 16. For example, the control unit 14 measures the communication quality of the propagation path by some method. Depending on the communication quality, the data rate is set to low speed (16QAM) or high speed (64QAM) and the switch circuit is switched.

  When the transmission data is to be transmitted at 16QAM, the control unit 14 according to the present embodiment controls the switch unit 16 so that the switch unit 16 supplies the packet data 108 to the 16QAM mapping circuit 18, and transmits the transmission data at 64QAM. If it should, the switch unit 16 is controlled so as to be supplied to the 64QAM mapping circuit 20.

  The switch unit 16 switches the route to the 16QAM mapping circuit 18 or the 64QAM mapping circuit 20 according to the control signal 106 and supplies the packet 108 to the mapping circuit 18 or 20.

  The 16QAM mapping circuit 18 performs mapping by allocating 4 bits per symbol on the basis of the packet 108 supplied via the switch unit 16, and outputs a constellation signal 110 indicating the resulting symbol string. The signal is supplied to the modulator 24 via 22. In 16QAM mapping, as shown in FIG. 3, 16 points are equally arranged in a space where I channel and Q channel are orthogonal, and 4 bits of data are allocated to each point to generate a symbol string. Generates a 16QAM constellation signal 110 for Gray code.

  Similarly to the 16QAM mapping circuit 18, the 64QAM mapping circuit 20 allocates and maps 6 bits per symbol on the basis of the packet 108 via the switch unit 16, and outputs the resulting constellation signal 112. The switch unit The signal is supplied to the modulator 24 via 22. In the 64QAM mapping, as shown in FIG. 4, 64 points are equally placed on the space consisting of the I and Q channels, and 6-bit data is allocated to each point. 112 is generated.

  In the present embodiment, the mapping circuits 18 and 20 arrange the 16QAM symbols and the corresponding 16 symbols of the 64QAM symbols so as to overlap in the IQ space, and the 16QAM symbols are related to these 16 overlapping symbols. The bit strings are allocated so that the 4 bits of the first 4 bits and the upper 4 bits of the 64QAM symbol are the same, and the constellation signals 110 and 112 are generated, respectively.

  For example, each point by 16QAM mapping and 64QAM mapping is arranged as shown in FIG. 3 and FIG. 4, respectively. In these figures, each arranged point is indicated by a circled number. 3 and 4, for example, the circle numbers 0, 1, 2,... 15 of 16QAM mapping overlap with the circle numbers 0, 2, 5,. .

  When the 16QAM mapping circuit 18 and the 64QAM mapping circuit 20 according to the present embodiment perform mapping processing on the predetermined bit string 108, as shown in FIG. 5, symbol strings 110 and 112 are generated by corresponding points overlapping each other. In FIG. 5, the symbol number indicates the order of the symbols in the symbol strings 110 and 112, and the I value and the Q value indicate the values of the respective points in the symbol strings 110 and 112.

  The switch unit 22 supplies the constellation signals 110 and 112 obtained from the mapping circuits 18 and 20, respectively, to the modulator 24 as the constellation signal 114. The modulator 24 modulates the constellation signal 114, and this embodiment Then, it converts into the transmission signal 116 and transmits.

  The demodulator 32 demodulates the received signal 132 received from the outside by the receiving device 30, converts it into a symbol string 134 and supplies it to the 64QAM demapping circuit 34 in this embodiment.

  The 64QAM demapping circuit 34 demaps the symbol sequence 134 obtained from the demodulator 32 by the 64QAM method, converts the symbol sequence 134 into a 64QAM bit sequence 136, and supplies it to the CRC detection circuit 36 and the thinning circuit 38.

  The CRC detection circuit 36 detects a CRC bit from the bit string 136 obtained from the demapping circuit 34, supplies a control signal 138 corresponding to the detection result to the thinning circuit 38, and controls the thinning circuit 38. When the signal cannot be detected, a control signal 138 for instructing execution of thinning is output.

  That is, when the CRC is OK, the CRC detection circuit 36 assumes that the reception signal 132 of the reception device 30 has been transmitted by 64QAM, and does not instruct the thinning process for the bit string 136 input to the thinning circuit 38 as it is. On the other hand, if the CRC is NG or an error, the reception signal 132 is transmitted as 16QAM, and the thinning process for the bit string 136 is instructed.

  The thinning circuit 38 performs thinning processing of the bit string 136 in accordance with the control signal 138 from the CRC detection circuit 36. When the CRC bit is detected by the CRC detection circuit 36, the thinning circuit 38 of the present embodiment assumes that the received signal 132 is transmitted by 64QAM, and uses the input bit string 136 as it is as the bit string 140 for the subsequent process. When the CRC bit is not detected, the received signal 132 is regarded as having been transmitted with 16QAM, and unnecessary bits are thinned out from the bit string 136, and the bit string 140 resulting from the thinning is output to the subsequent process. To do.

  This decimation circuit 38 performs decimation processing when, for example, a received signal modulated by 16QAM is demodulated by 64QAM, that is, removes or discards the lower 2 bits of the bit string 136 of 6 bits per symbol as unnecessary. Thinning out.

  Next, an operation example of transmitting and receiving packet data by the 16QAM system in the transmission device 10 and the reception device 30 in the present embodiment will be described with reference to the sequence chart of FIG.

  In this embodiment, when the transmission processing of the packet data 102 is started in the transmission device 10, this packet data 102 is first supplied to the CRC generation circuit 12 (S102), for example, a 104-bit packet as shown in FIG. Data 102 is input to the CRC generation circuit 12. In FIG. 7, since this data 102 is transmitted by the 16QAM system, 4 bits are allocated per symbol.

In the CRC generation circuit 12, for example, the International Telegraph and Telephone Consultative Committee (CCITT: Comite Consultatif)
The CRC CRC is generated by applying the polynomial CRC-16 according to International Telegraphique et Telephonique), and as shown in FIG. 8, the 16-bit CRC bit is added to the 104-bit packet data 102 to obtain the 120-bit packet data 104. It is generated (S204) and supplied to the switch unit 16.

  In the transmitting apparatus 10, the control unit 14 selects the transmission modulation method of the packet data 102 (S206). In this embodiment, the 16QAM method is selected, and the control signal 106 corresponding to the selection result is sent to the switch unit 16. To be supplied. The packet data 104 input to the switch unit 16 is supplied to the 16QAM mapping circuit 18 as packet data 108 in response to the control signal 106.

  In the 16QAM mapping circuit 18, the 120-bit packet data 108 is mapped for 16QAM (S208), converted into a constellation signal 110 indicating 30 symbol strings as shown in FIG. It is supplied to the modulation unit 24. At this time, the packet data 108 is processed by 16QAM mapping corresponding to 64QAM mapping, for example, as shown in FIG.

  The modulation unit 24 modulates the constellation signal 114 obtained via the switch unit 22 to generate a transmission signal 116 (S212), and transmits the signal to the outside, for example, toward the reception device 30 (S214).

  On the other hand, when the transmission signal 116 from the transmission device 10 is received as the reception signal 132 in the reception device 30 of the present embodiment, the reception signal 132 is first supplied to the demodulator 32 and demodulated (S214), The symbol sequence 134 is restored.

  This symbol sequence 134 is supplied to the 64QAM demapping circuit 34 and demapped by the 64QAM method (S216). In this embodiment, the symbol sequence 134 is converted into 30 bit sequences 136 of 6 bits per symbol as shown in FIG. It is supplied to the CRC detection circuit 36 and the thinning circuit 38.

  The CRC detection circuit 36 detects CRC bits based on the bit string 136 (S218). In the bit string 136 shown in FIG. 10 of the present embodiment, the lower two bits of each symbol are converted into data by 64QAM in 16QAM. Since it is an extra bit that is added due to demapping, the CRC check results in an error.

  At this time, in the CRC detection circuit 36, the received signal 132 can be transmitted in the 16QAM system in response to the CRC check in error, and the control signal 138 instructing execution of the thinning process is supplied to the thinning circuit 38. Is done.

  Further, in the thinning circuit 38, the bit string 136 is thinned in accordance with the control signal 138 (S220), and the lower 2 bits of each symbol are removed to generate an appropriate bit string 140 of 4 bits per symbol. Thereafter, the bit string 140 is supplied to a required subsequent process in the receiving circuit 30.

  Next, an operation example of transmitting and receiving packet data by the 64QAM system in the transmission device 10 and the reception device 30 in the present embodiment will be described with reference to the sequence chart of FIG.

  In this embodiment, when the transmission processing of the packet data 102 is started in the transmission device 10, this packet data 102 is first supplied to the CRC generation circuit 12 (S102), for example, a 164 bit packet as shown in FIG. Data 102 is input to the CRC generation circuit 12. In FIG. 11, since this data 102 is transmitted by the 64QAM system, 6 bits are assigned per symbol.

  In the CRC generation circuit 12, a CRC bit is generated by adapting a polynomial CRC-16 by CCITT, for example, and as shown in FIG. 12, a 16-bit CRC bit is added to a 164-bit packet data 102 to create a 180-bit packet. Data 104 is generated (S204) and supplied to the switch unit 16.

  In the transmission apparatus 10, the control unit 14 selects the transmission modulation method of the packet data 102 (S206), and in this embodiment, the 64QAM method is selected, and the control signal 106 corresponding to the selection result is sent to the switch unit 16. To be supplied. The packet data 104 input to the switch unit 16 is supplied to the 64QAM mapping circuit 20 as packet data 108 in response to the control signal 106.

  In the 64QAM mapping circuit 20, the 180-bit packet data 108 is mapped for 64QAM (S208), converted into a constellation signal 112 indicating 30 symbol strings as shown in FIG. It is supplied to the modulation unit 24.

  In the modulation unit 24, the constellation signal 114 from the switch unit 22 is modulated to the transmission signal 116 in step S212, and the transmission signal 116 is transmitted to the reception device 30 in step S214.

  On the other hand, in the receiving device 30 of the present embodiment, when the transmission signal 116 from the transmitting device 10 is received as the received signal 132, the received signal 132 is received by the demodulator 32 in step S214 in the same manner as described above. The symbol sequence 134 is demodulated into a symbol sequence 134. The symbol sequence 134 is demapped by the 64QAM demapping circuit 34 in step S216 and converted into a 6-bit bit sequence 136 per symbol, which is then sent to the CRC detection circuit 36 and the thinning circuit 38. Supplied.

  In the CRC detection circuit 36, CRC bits are detected based on the bit string 136 (S218). In this embodiment, since the CRC check does not cause an error, the received signal 132 can be transmitted in the 64QAM system, A control signal 138 that does not instruct processing is supplied to the thinning circuit 38.

  Further, in the thinning circuit 38, the bit string 136 is not thinned according to the control signal 138, and then the bit string 136 is supplied as it is as the bit string 140 to the required subsequent process in the receiving circuit 30.

  Further, the transmission modulation scheme by the transmission apparatus 10 and the reception apparatus 30 of the present invention may be configured in combination with other communication schemes such as an Orthogonal Frequency Division Multiplex (OFDM) scheme, for example.

It is a block diagram which shows one Example of the transmitter which concerns on this invention. It is a block diagram which shows one Example of the receiver which concerns on this invention. It is an example of the symbol arrange | positioned by 16QAM mapping in the transmitter of the Example shown in FIG. It is an example of the symbol arrange | positioned by the 64QAM mapping in the transmitter of the Example shown in FIG. It is an example of the symbol sequence mapped by the transmission apparatus of the Example shown in FIG. It is a sequence chart explaining the operation | movement procedure in the transmitter of the Example shown in FIG. 1 and FIG. 2, and a receiver. It is an example of a 16QAM bit string processed by the transmission apparatus of the embodiment shown in FIG. It is an example of the bit sequence which added the CRC bit to the 16QAM system bit sequence shown in FIG. 9 is an example of a symbol sequence obtained by converting the 16QAM format bit sequence shown in FIG. 8 by 16QAM mapping. 10 is an example of a bit string obtained by converting the 16QAM system symbol string shown in FIG. 9 by 64QAM demapping by the receiving apparatus of the embodiment shown in FIG. It is an example of a 64QAM system bit string processed by the transmission apparatus of the embodiment shown in FIG. 12 is an example of a bit string obtained by adding a CRC bit to the 64QAM system bit string illustrated in FIG. 11. It is an example of the symbol sequence which converted the 64QAM system bit sequence shown in Drawing 12 by 64QAM mapping.

Explanation of symbols

10 Transmitter
12 CRC generation circuit
14 Control unit
16, 22 Switch part
18 16QAM mapping circuit
20 64QAM mapping circuit
24 modulator
30 Receiver
32 Demodulator
34 64QAM demapping circuit
36 CRC detection circuit
38 Thinning out circuit

Claims (16)

In a digital communication system that transmits and receives packet data at a data rate according to any QAM method among a plurality of quadrature amplitude modulation (QAM) methods, the system includes:
Cyclic Redundancy Check (CRC) bits are added to data to be transmitted, a modulation scheme of the data to be transmitted is selected from the plurality of QAM schemes, and a plurality of QAM schemes corresponding to each of the plurality of QAM schemes are selected. A transmission unit that performs mapping processing corresponding to the selected QAM method among the mapping processing on the data to be transmitted, and modulates and transmits the data after the mapping processing;
The received data is demodulated and subjected to predetermined demapping processing. CRC detection is performed based on the data after the predetermined demapping processing. If CRC cannot be detected, the data after the predetermined demapping processing is processed. And a receiving means for performing a thinning process.   2. The digital communication system according to claim 1, wherein the system has a spatial arrangement of symbols according to a predetermined low-speed data rate modulation scheme among the plurality of QAM schemes, and a predetermined high-speed data rate among the plurality of QAM schemes. A digital communication system, wherein the plurality of mapping processes and the predetermined demapping process are performed so as to overlap corresponding to a spatial arrangement of symbols by a modulation method. 3. The digital communication system according to claim 2, wherein the predetermined low-speed data rate modulation method is a 16QAM method.
The predetermined high-speed data rate modulation method is a 64QAM method,
The transmitting device performs mapping processing corresponding to one of the QAM schemes of 16QAM and 64QAM as the plurality of QAM schemes,
The receiving means receives the packet data transmitted at a data rate corresponding to any of 16QAM and 64QAM as the plurality of QAM schemes, and transmits the received data as the predetermined demapping process. A digital communication system that performs demapping for 64QAM regardless of the data rate at the time. 4. The digital communication system according to claim 3, wherein the system maps the plurality of mappings such that the upper 4 bits of a 6-bit value assigned to a symbol according to 64QAM is equal to 4 bits assigned to a symbol according to 16QAM. Process and the predetermined demapping process,
The digital communication system, wherein the thinning-out process removes lower two bits of the data after the predetermined demapping process. In a communication method of packet data transmitted and received at a data rate according to any QAM method among a plurality of QAM methods, the method includes:
When transmitting the packet data, a CRC bit is added to the data to be transmitted, a modulation scheme of the data to be transmitted is selected from the plurality of QAM schemes, and a plurality of mappings corresponding to each of the plurality of QAM schemes Among the processes, the mapping process corresponding to the selected QAM method is performed on the data to be transmitted, the data after the mapping process is modulated and transmitted,
When receiving the packet data, the received data is demodulated and subjected to a predetermined demapping process, CRC detection is performed based on the data after the predetermined demapping process, and if the CRC cannot be detected, the predetermined data A communication method characterized by performing a thinning process on data after a demapping process.   6. The communication method according to claim 5, wherein a spatial arrangement of symbols according to a predetermined low-speed data rate modulation scheme among the plurality of QAM schemes is a predetermined high-speed data rate modulation among the plurality of QAM schemes. A communication method, wherein the plurality of mapping processes and the predetermined demapping process are performed so as to overlap corresponding to a spatial arrangement of symbols according to a method. The communication method according to claim 6, wherein the predetermined low-speed data rate modulation method is a 16QAM method,
The predetermined high-speed data rate modulation method is a 64QAM method,
When transmitting the packet data, as the plurality of QAM schemes, a mapping process corresponding to any of 16QAM and 64QAM QAM scheme is performed,
When receiving the packet data, as the plurality of QAM schemes, the packet data transmitted at a data rate according to any one of 16QAM and 64QAM is received, and received as the predetermined demapping process A communication method characterized by performing demapping for 64QAM regardless of the data rate at the time of data transmission. 8. The communication method according to claim 7, wherein the plurality of mapping processes are performed such that upper 4 bits of a 6-bit value assigned to a symbol according to 64QAM is equal to 4 bits assigned to a symbol according to 16QAM. And performing the predetermined demapping process,
The thinning-out process removes the lower 2 bits of the data after the predetermined demapping process. Among a plurality of QAM schemes, in a receiving device that is mapped according to any QAM scheme and receives packet data transmitted at a data rate according to the QAM scheme, the apparatus includes:
When the packet data with the CRC bit added is received, the received data is demodulated and subjected to predetermined demapping processing, CRC detection is performed based on the data after the predetermined demapping processing, and CRC cannot be detected In the receiving apparatus, a thinning process is performed on the data after the predetermined demapping process. The receiving device according to claim 9, wherein the device is configured such that a spatial arrangement of symbols by a predetermined low-speed data rate modulation method among the plurality of QAM methods is a predetermined high-speed data rate modulation among the plurality of QAM methods. Receiving the packet data mapped so as to overlap corresponding to the spatial arrangement of symbols according to the scheme;
Performing the predetermined demapping process on data arranged so that a spatial arrangement of symbols according to the predetermined low-speed data rate modulation scheme overlaps with a spatial arrangement of symbols according to the predetermined high-speed data rate modulation scheme. A receiving device. The receiving apparatus according to claim 10, wherein the predetermined low-speed data rate modulation scheme is a 16QAM scheme,
The predetermined high-speed data rate modulation method is a 64QAM method,
The apparatus is mapped as the plurality of QAM schemes according to any of 16QAM and 64QAM QAM schemes, receives the packet data transmitted at a data rate according to the QAM scheme, and receives the predetermined demapping A receiving apparatus characterized by performing 64QAM demapping regardless of a data rate at the time of transmission of received data as processing. 12. The receiving apparatus according to claim 11, wherein the apparatus maps the packet data in which the upper 4 bits of a 6-bit value assigned to a symbol based on 64QAM are equal to 4 bits assigned to a symbol based on 16QAM. Receive
For the data arranged so that the upper 4 bits of the 6-bit value assigned to the symbol in the 64QAM system are equal to the 4 bits assigned to the symbol in the 16QAM system, the predetermined demapping process is performed,
The receiving apparatus, wherein the thinning process removes lower 2 bits of the data after the predetermined demapping process. In a method of receiving packet data that is mapped according to one of the QAM schemes among a plurality of QAM schemes and transmitted at a data rate according to the QAM scheme, the method includes:
When the packet data with the CRC bit added is received, the received data is demodulated and subjected to predetermined demapping processing, CRC detection is performed based on the data after the predetermined demapping processing, and CRC cannot be detected Includes a thinning-out process on the data after the predetermined demapping process. 14. The reception method according to claim 13, wherein the spatial arrangement of symbols according to a predetermined low-speed data rate modulation scheme among the plurality of QAM schemes is a predetermined high-speed data rate modulation among the plurality of QAM schemes. Receiving the packet data mapped so as to overlap corresponding to the spatial arrangement of symbols according to the scheme;
Performing the predetermined demapping process on data arranged so that a spatial arrangement of symbols according to the predetermined low-speed data rate modulation scheme overlaps with a spatial arrangement of symbols according to the predetermined high-speed data rate modulation scheme. A characteristic reception method. 15. The reception method according to claim 14, wherein the predetermined low-speed data rate modulation scheme is a 16QAM scheme,
The predetermined high-speed data rate modulation method is a 64QAM method,
In the method, as the plurality of QAM schemes, mapping is performed according to any one of 16QAM and 64QAM, and the packet data transmitted at a data rate according to the QAM scheme is received, and the predetermined demapping is performed A receiving method characterized in that 64QAM demapping is performed as processing regardless of the data rate at the time of transmission of received data. 16. The reception method according to claim 15, wherein the packet data is mapped such that upper 4 bits of a 6-bit value assigned to a symbol according to 64QAM are equal to 4 bits assigned to a symbol according to 16QAM. Receive
For the arranged data, the plurality of mapping processes and the predetermined demapping process are performed so that the upper 4 bits of the 6-bit value assigned to the symbol by the 64QAM system is equal to the 4 bits assigned to the symbol by the 16QAM system. Done
The reception method according to claim 1, wherein the thinning-out process removes lower 2 bits of the data after the predetermined demapping process.

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